Alternative Renewable Energy Sources Research Articles

Ocean Wave Energy Conversion: A Review

The globally increasing demand for energy has encouraged many countries to search for alternative renewable sources of energy. To this end, the use of energy from ocean waves is of great interest to coastal countries. Hence, an assessment of the available resources is required to determine the appropriate locations where the higher amount of wave energy can be generated. The current paper presents a review of the resource characterizations for wave energy deployment. The paper gives, at first, a brief introduction and background to wave energy. Afterward, a detailed description of formulations and metrics used for resource characterization is introduced. Then, a classification of WECs (wave energy converters) according to their working principle, as well as PTO (power take off) mechanisms used for these WECs are introduced. Moreover, different sources for the long-term characterization of wave climate conditions are reviewed, including in situ measurements, satellite altimeters, and data reanalysis on one hand, and numerical simulations based on spectral wave models on the other hand. Finally, the review concludes by illustrating the economic feasibility of wave farms based on the use of the levelized cost of the energy index.

Utilization of Biomass Waste Through Small-Scale Gasification Technology in the Eastern Cape Province in South Africa: Towards the Achievement of Sustainable Development Goal Number 7

Despite being resource-richly endowed with various energy sources, and despite the connection of 89.8% of the households to the grid in South Africa, the Eastern Cape province, as compared to other provinces, has the lowest level of grid connection of about 64.5%. Some of the rural poor households in the Eastern Cape province supplement their free basic electricity with unclean energy alternatives. Using unclean energy alternatives is not only detrimental to the environment and health of the people, but it is a sign of energy poverty and among the contributing factors to depesantization, deagrarianization, and deindustrialization which prolongs the underdevelopment in rural areas. Innovation in energy technologies is a key ingredient in meaningful rural development. The utilization of small-scale biomass gasification technologies can be a solution to the South African energy crisis in rural areas, and it is in line with sustainable development goal number 7, which is about ensuring access to affordable, reliable, sustainable, and modern energy for all. Alternative renewable energy sources cannot be ignored when dealing with the energy crises in South Africa. Renewable energy sources in the country include biomass, solar, wind, and hydropower. Despite its low utilization in the Eastern Cape province, small-scale biomass gasification technology remains pivotal in reducing energy crisis by producing electricity. However, the affordability of biomass gasification technology also plays a role in whether people will accept small-scale biomass gasification technology. The purpose of this paper is to determine the possibilities of using small-scale biomass gasification technology. This paper gives a comprehensive review of small-scale biomass gasification technology potential in the Eastern Cape province and the link between acceptance of small-scale gasification technology and affordability by evaluating the availability of biomass sources in the province and achievements with regards to small-scale biomass gasification. This paper also covers the impact of biomass gasification technology integration in the energy grid, what needs to be taken into consideration before its installation, its benefits and the barriers to its development in Eastern Cape province.

Evaluating the Performance of Agricultural Tractor Engine using Cottonseed Oil Biodiesel

The energy demand has been significantly increasing around the world in the last century. Conventional fossil fuels as one of the sources has been highly demanded due to its negative environmental effect. The growing demand for energy stimulated the development of renewable and eco-friendly alternative energy sources. Produced from vegetable oils and animal fats, biodiesel is a renewable, sustainable, and biodegradable fuel. It can be used as an alternate fuel to conventional diesel (CD) in compression ignition (CI) engines. The Belarus 920 tractor, with a maximum output of 74.5kW, was put through a Power Take Off (PTO) test in this study to assess its performance and emission components when fueled with conventional petroleum diesel, B20, B50, and B100 of Cotton Seed Oil Biodiesel (CSOME). The performance results showed that the power and Break Thermal Efficiency (BTE) fell, while the BSFC improved, when the tractor was fueled with neat CSOME and its mixes.

Valorization and optimization of Prosopis africana pod and cowpea husk wastes for densified hybrid briquette production

Biomass is an eco-friendly alternative sustainable renewable energy source when agricultural wastes are effectively utilized. It has become critical to assess the suitability of biofuel briquettes as an energy source for cooking, electricity, and fuel for heating. Certainly, the integration of energy sources into energy policies is warranted, considering the huge potential to provide energy for rural communities and the peri-urban poor with alternative fuel. This research describes a technique to generate densified hybrid solid biofuels from biomass waste and valorize them. Prosopis africana pod (PAP) and cowpea husk (CPH) wastes were combined to create high-energy-density fuel briquettes. The experiment involves improving briquette manufacturing parameters using response surface methodology to better understand the impacts of particle sizes, composition, binder concentrations, and densification pressures on briquette performance. The optimal conditions were particle size 150 µm, 50% PAP, 10% binder concentration, and densification pressure 103.42 kN/m2. The optimum values for burning rate, ignition time, specific fuel consumption, and heating value were 0.35 g/min, 2.75 min, 0.186 g/L, and 22.98 MJ/kg, respectively. The findings show the potential for using PAP and CPH biomass waste to produce environmentally friendly energy sources. This increases the potential agro-waste feedstocks for bioenergy in developing countries, reducing energy insecurity while promoting waste management, renewable energy generation, and environmental sustainability.

Design, Fabrication, and Testing of Small Wind Pump

The demand for energy used to pump water for irrigation has been increasing, resulting in the need for alternative renewable energy sources to reduce costs. A study was conducted to develop a small wind pump that could be used to irrigate crops. The wind pump's efficiency, discharge, and actual power generated were evaluated, and regression analysis and the coefficient of determination were used to determine the goodness of fit. Results showed that the wind pump required a minimum wind speed of 0.3 m/s produced a discharge of 0.95 L/min, while a 4.13m/s wind speed produced a water discharge of 5.45 L/min. The efficiency of the wind pump was measured using the regression equation E= - 04075(ws)² - 0.6375(ws) + 14.36, where R² = 0.6201, resulting in a maximum efficiency of 20.56% and a minimum of 5.57%. This indicates that the wind pump was efficient at low wind speeds due to the dynamic stress of the pump lift rod and a mismatch between the rotor and pump characteristics. Lastly, the net benefit of Php 25,083.61 per year was derived, with a return on investment of 33.86%, which will be paid back in 1.26 months.

Engineering lipase TLL to improve its acid tolerance and its biosynthesis in Trichoderma reesei for biodiesel production from acidified oil

Lipases catalyze the synthesis of biodiesel, which is an important renewable alternative energy source. Cost-efficient conversion of waste acidified oil to biodiesel entails acid-tolerant lipases which have not been extensively studied. This study showed that the commonly used Thermomyces lanuginosus lipase TLL displayed a weak acid tolerance and an unsatisfactory performance in biodiesel production from acidified oil. Directed evolution of TLL identified one TLL-T3 variant with three residue substitutions (A69S/V150P/N222G). TLL-T3 displayed significantly enhanced acid tolerance, and its application in acidified oil treatment led to a biodiesel yield up to 90 % (w/w). A scaled-up production of TLL-T3 in Trichoderma reesei was further achieved and the highest extracellular lipase activity reached 16,123 U/mL after fermentation optimization. These results provide new insights into structural adaptation to acid tolerance by lipases and show that TLL-T3 holds great potential in commercial biodiesel production from waste acidified oil.

CROWDFUNDING AND FUNDRAISING AS INNOVATIVE FINANCIAL TOOLS IN PROVIDING ALTERNATIVE ENERGY SOURCES

Objectives. Search and substantiation of directions for investing investment resources in alternative energy sources using crowdfunding and fundraising mechanisms. Method. Research methods in this scientific article are statistical, logical, historical, graphic, as well as general methods of scientific thinking: analysis, synthesis, induction, deduction. The results. The existence of the problem of insufficient financial instruments for building a system of alternative regenerative energy sources is substantiated. The necessity of an in-depth study and analysis of the financial tools of crowdfunding and fundraising for more effective provision of financial resources for the production of alternative renewable energy sources has been proven. Scientific novelty. The need for innovative financial instruments for "green" projects of renewable sources of energy resources has been identified. It is proposed and justified to use fundraising and crowdfunding start-up projects for the most optimal financing of social, so-called "green" investments in renewable energy sources at the current stage of the military crisis. Practical significance. The practical implementation of the proposed measures for the development of innovative projects based on fundraising and crowdfunding in the system of alternative renewable energy sources in the conditions of a crisis state of the economy will save financial resources and increase the profitability of domestic enterprises in the energy sector, which will have a positive effect on the general macroeconomic situation in the state.

Bio-Briquettes Production from Spent Coffee Grounds, Composite Organic Waste, and Coconut Shells by Using Carbonization

Abstract Global energy demand is projected to rise in coming years due to a corresponding increase in the world’s population. This increased demand highlights the importance of exploring alternative energy sources, particularly renewable energy. Among the various forms of renewable energy, biomass stands out as a consistently abundant and accessible source of renewable energy on a global scale. In Indonesia, there exists a significant abundance of organic waste, spent coffee grounds, and coconut shells. Each of these wastes has a high heating value, so it has potential to become the raw material of bio-briquette, an alternative source of renewable energy. By the method of carbonization, the study was intended to identify the characteristics of the bio-briquette composite using organic waste, coconut shells, and spent coffee grounds as raw material on proximate analysis parameters and heating value. Based on the results of the research, the best bio-briquette characteristics were obtained from sample APEK25 with the characteristic of 7.84% water content, 36.24% volatile matter, 9.38% ash content, 46.54% fixed carbon, and a heating value is 4637 cal/gr. These findings highlight the potential of bio-briquettes as a renewable energy, contributing to waste management for sustainable energy transition and addressing the increasing energy demand.

Preliminary findings on the potential of converting municipal solid waste into refuse-derived fuel as an alternative renewable energy source from the Jakarta waste case study

Abstract The conversion of municipal solid waste (MSW) to refuse-derived fuel (RDF) is a promising technology for addressing waste management issues and obtaining a sustainable source of renewable energy. However, the implementation of RDF technology for MSW management in Indonesia, particularly in urban areas, has not yet been realized. This study aims to evaluate the viability of producing RDF from MSW, specifically the waste generated by Jakarta city, which is representative of other large cities in Indonesia. The research analyzed the MSW, including its physical and chemical properties, such as composition, proximate and ultimate analysis, and energy content. In order to investigate the potential adoption of bio-drying technology for the production of RDF from waste in Jakarta, a pilot scale experiment was conducted using a batch system. The results of the characterization indicate that the sample comprises of more than 50% organic waste, and furthermore, the moisture content in the samples is greater than 60%. The waste typically contains a carbon content of around 50% and a calorific value of approximately 1400 kcal/kg. RDF products produced through bio-drying can achieve a moisture content of 37.88% and a heating value of 2675 kcal/kg. The results further emphasize the potential of the produced RDF as a feasible source of renewable energy.

Copper/ cerium metal organic frame work as highly efficient structures for solar power-induced hydrogen generation through the process of water splitting

Increased dependence on fossil fuels as energy sources strongly contributes in both global warming and environmental pollution, leading to serious impacts on human-beings and societies. Therefore, shift from hydrocarbon-based energy to alternative green, sustainable and renewable sources of energy has been globally stimulated in past decades. In an agreement with this context, hydrogen is counted as one of these sources which has been paid strong attention recently due to its high energy content and no harmful emissions. Consequently, this study introduces production of clean green hydrogen through the process of photocatalytic water splitting which is a cost-effective route and releases zero emissions. A series of copper/ or cerium based metal–organic frameworks were successfully prepared via one-pot solvothermal technique and were presented as three novel photocatalysts for hydrogen production from water. The photocatalytic performances of these structures were investigated under visible light irradiation, revealing the highest activity for copper doped cerium metal–organic framework. It exhibited a maximum pure hydrogen productivity of 465 mmol per hour/ gram which was much higher than those the detected productivity by copper and cerium metal–organic frameworks (289 and 375 mmol per hour/ gram respectively). Heterojunction between the two central metals as well as effective charge separation in copper doped cerium metal–organic framework are reasons of its superiority in hydrogen evolution exploit, compared to the other two structures. The recyclability of copper doped cerium metal–organic framework demonstrated high reliability since it showed nearly stable yields of hydrogen over ten cycles of photocatalytic reuse. Therefore, the presented binary metals organic framework establishes new platform for photocatalysts in process of hydrogen production through water splitting.

Harnessing the clean energy: Phosphorus-alkynyl covalent organic frameworks for photocatalytic hydrogen production

Given the diminishing reserves of fossil fuels, the development of renewable alternative energy sources is of global importance. Photocatalytic hydrogen (H2) evolution stands out as a promising and cost-effective method to harness sunlight for producing carbon-free H2 fuel. Recently, two-dimensional (2D) covalent organic frameworks (COFs) have garnered considerable research interest in photocatalysis on account of their exceptional surface area and predictable assembly of diverse molecules with adjustable electronic properties. Herein, six 2D COFs are constructed by topologically assembling phosphorus-alkynyl functional moieties and benzene-based building units, including benzene (COF-1), triazine (COF-2), heptazine (COF-3), triphenyl-benzene (COF-4), triphenyl-triazine (COF-5), and triphenyl-heptazine (COF-6), employing first-principles calculations. Our computational results illustrate that the variation of benzene-based building units significantly regulates the electronic structures of COFs, all of which possess semiconductor properties with tunable bandgaps spanning from 1.56 to 2.56 eV. Of particular importance, COF-1, COF-2, COF-4, COF-5, and COF-6 can spontaneously stimulate the hydrogen evolution reaction (HER) under their own light-induced bias without the need for sacrificial agents and co-catalysts. Among them, COF-4 and COF-5 show the best HER activity without light-induced bias, with ΔG values of 0.02 and −0.01 eV, respectively, whose excellent photocatalytic performance can be ascribed to their appropriate electronic band structures, pronounced optical absorption, and low work functions. This finding offers profound insights for exploring other highly efficient HER photocatalysts.

Cutting-edge advances in alga Botryococcus for eco-friendly biofuels and high-value bioproducts — A critical review

Currently, natural product demand is increasing along with environmental sustainability and health-conscious lifestyle trends, in addition, sustainable energy use is also driving this demand. In recent years, algae based biorefineries have drawn a lot of attention. In this context, alga Botryococcus sp. has shown as a potential feedstock for a number of industries which includes cosmetics, nutraceuticals, medicines, and fuel. The alga Botryococcus produce a renewable and biodegradable alternative energy source in comparison to fossil fuels. The utilization of alga Botryococcus derived biodiesel can reduce the greenhouse gases emission during combustion, which lowers the carbon footprint overall. Understanding the most effective algae cultivation methods and production technologies is essential to fully utilize its potential in tackling the world's energy demands, uncertain climate change, and satisfying the increasing need for freshwater resources. Thus, this review demonstrates the importance of alga Botryococcus as a multifaceted source by thoroughly examining its properties. It also describes the opportunities and problems that Botryococcus faces moving forward in the context of a circular bioeconomy.

Regional power duration curve model for ungauged intermittent river basins

ABSTRACT Hydropower is a sustainable and renewable energy source that can serve as a practical and economically viable solution to the future possible energy crisis and climate change scenarios. Moreover, it possesses a higher energy density compared to other alternative renewable energy sources such as solar, wind energy, etc. In order to determine the potential of hydropower, long-term observed hydrometeorological data of streamflow, precipitation, etc. are crucial. This study investigates a new power duration curve (PDC) methodology. Basin characteristics such as drainage area and basin relief with meteorological data as precipitation are used for regional models in the application. The classification based on geographical locations is made for regional models. Six models based on equation type were utilized to determine the optimal regional model. Absolute errors of cease-to-flow point estimates ranging from 0.01 to 11.49% were observed. The model provided successful results according to Nash–Sutcliffe efficiency which is widely used in hydrological studies very close to 1 and higher than 0.87 except for one streamflow gauging station therewithal all other calculated performance metrics. It is observed that power and cease-to-flow point estimates of intermittent rivers can be obtained with a new PDC model based on basin characteristics.

Stable and efficient hydrogen evolution activity of tungsten-incorporated nanocrystalline perovskite BaSnO3 electrocatalyst

The increasing demand in energy consumption and alarming environmental concern is compelling to develop alternative renewable and clean energy sources. Hydrogen (H2) is identified as a potential candidate due to its abundance, high gravimetric energy density, and no carbon footprint. Presently, splitting of water is a highly promising method for sustainable hydrogen generation, and the key challenge is to develop a stable and high-performing electrocatalysts for H2 evolution reaction (HER) as a renewable energy source. Metal oxides are excellent alternative electrocatalysts to noble metals due to their cost effectiveness, tunability and abundance. Ternary perovskite barium stannate (BaSnO3) has been intensely explored for water splitting and electrocatalysis related applications. Tungsten (W) 1 % incorporated BaSnO3 synthesized by facile hydrogen peroxide route is explored as an electrocatalyst for HER activity in acidic medium for the first time. The pure and W-incorporated BaSnO3 exhibited promising HER activity with an overpotential value of 233 and 295 mV at 10 mA/cm2 with enhanced electrochemical surface area of 7.309 and 3.075 Fcm−2, respectively. A 12-hour stability test not only concluded the durability and performance of H2 evolution activity but also confirmed the enhanced initial current density for the W-incorporated BaSnO3 sample.

Kajian Tekno Ekonomi Terkait Konversi Limbah Biomassa Refuse Derived Fuel (RDF) Menjadi Listrik Melalui Metode Gasifikasi Tiga Tingkat dan Mesin Diesel Dual Fuel di Pulau Batam

The increasing energy demand has led to a decrease in the availability of fossil fuels, making it necessary to seek renewable alternative energy sources. One of the alternative energy solutions that is currently being widely developed is biomass. Biomass can be converted into renewable energy through a process called gasification. Gasification is the conversion process of solid fuels, often referred to as Municipal Solid Waste (MSW), which can be processed into Biomass Refuse Derived Fuel (RDF) for the three-stage gasification process to produce syngas. Syngas can then be used as fuel for diesel engines to generate electricity in a “Waste to Electric” system. This study utilizes a diesel engine with a dual-fuel system. The objective of operating the diesel engine with a dual-fuel system is to determine the impact of using syngas, obtained from the gasification of RDF pellets, in a diesel engine with a dual-fuel system. The dual-fuel diesel system operates using two types of fuel: diesel fuel and gas fuel. The gas fuel used is syngas resulting from the gasification of RDF biomass pellets. During the gasification process, variations in the air ratio will be adjusted in the pyrolysis, oxidation, and reduction zones with air ratio comparisons of 0:10:0, 1:8:1, 2:7:1, and 1:7:2. The syngas produced from the gasification process will be used as fuel for the dual-fuel diesel engine. The performance characterization of the dual-fuel diesel engine will be conducted by testing the engine at 5000 rpm with load variations from 500 watts to 5000 watts in 500-watt increments, and by varying the mass flow rate of the syngas by adjusting the syngas valve opening. This study aims to demonstrate that RDF has promising potential as a renewable electricity source. The three-stage gasification process has proven effective in converting RDF into high-quality syngas. The dual-fuel diesel engine can operate stably and produce electricity with lower emissions compared to conventional diesel engines. The utilization of RDF biomass waste for power generation through three-stage gasification and dual-fuel diesel engines offers a sustainable solution to waste management issues and provides environmentally friendly electricity on Batam Island.

DYNAMIC MODELLING OF THREE-PHASE MICROGRIDS INCLUDING DQ0 CURRENT CONTROLLED PHOTOVOLTAIC GENERATION UNDER TRANSIENT CONDITIONS

ABSTRACT: The photovoltaic generation can be interconnected to power systems or to insulated grids to satisfy the growing electrical demand as an alternative renewable energy source. The photovoltaic generator dynamics affects the control, protection, stability, and power quality of the electrical grid, this network dynamics requires to be examined and conveniently regulated and adjusted. The dynamic averaged model for the dq0 current controlled DC/AC inverter is applied to obtain the time-domain response to electromagnetic transients under special conditions such as electrical load fluctuations, unbalanced faults, voltage and current transients to verify e.g., the ride through capability or to adjust the protection and control devices, these transients can be present during the operation of electrical microgrids and power systems interconnected with photovoltaic generation. The system modelling includes the photovoltaic plant interconnected with the microgrid using the dq0 current controlled DC/AC inverter. The case studies are applied to analyse three-phase electrical microgrids, their time-domain response, and the obtained voltage and current waveforms can be used to verify the dynamic behaviour and stability of the electrical system interconnected with photovoltaic generation and similarly to verify the operation of the dq0 current controller for the inverter. The results can be used to control the microgrid dynamic behaviour. Keywords: current control, dq0 transform, inverter, microgrids, photovoltaic generation, power quality, protection, time-domain, transients, unbalanced faults, unbalanced voltage sags, voltage source converter

Valorization of lignocellulosic biomass: Progress in the production of second-generation bioethanol

Cellulosic ethanol, a biofuel product derived from microbial fermentation of cellulose-rich agricultural waste biomass, holds the potential to significantly contribute to sustainable development, energy security, and environmental friendliness as a green and renewable alternative energy source. Cellulosic ethanol offers remarkable energy benefits and carbon emission reductions. However, the biorefining process of cellulosic ethanol faces challenges and complexities. This article revolves around five aspects: feedstock, composition, pretreatment, cellulase hydrolysis, and ethanol fermentation processes in the biorefining of cellulosic ethanol. It provides an overview of the process flow and characteristics of cellulosic ethanol biorefining, emphasizing its significance. The main technological bottlenecks in cellulosic ethanol production are analyzed. Recent research advancements in cellulosic ethanol biorefining are summarized, followed by an outlook on the research focus and future prospects in the field of cellulosic ethanol.

Impact of energy imports, renewable electricity production, alternative, and nuclear energy sources on natural gas resource rents.

The world faces several problems related to natural gas resource rents and energy production from renewable sources. One of the main problems is the influence of energy imports, manufacturing exports, and alternative energy sources on natural gas and electricity production from renewable sources. Energy imports, manufacturing exports, and alternative energy sources can impact natural gas and electricity production. This paper examines natural gas resource rents and electricity production from renewable sources nexus from 1971 to 2021, using energy imports, manufacturer's exports, and alternative energy sources in China. Electricity production from renewable sources and manufacturing exports are negatively associated with natural gas resource rents. Energy imports and alternative energy sources positively relate to natural gas resource rents in China. These results suggest that the energy sector in China is highly interconnected and that policies that seek to promote renewable energy sources and other alternatives can positively affect natural gas resource rents. China needs to develop an energy policy considering the policy implications of energy imports and natural gas resource rents. Such a policy should focus on increasing domestic production, reducing energy imports, and ensuring adequate revenue from natural gas resource rents. Additionally, regulations could be implemented that support the development of alternative energy sources, such as requiring utilities to purchase a certain percentage of their power from renewable sources.

Micro Hydro Power Site Characterization in Indonesia: Variable Optimization for Site Selection Using GeoDetector and RFE-Random Forest

Abstract Micro hydropower (MHP) systems are a promising alternative renewable and sustainable energy source to conventional fossil fuels, particularly in regions with abundant water resources like Indonesia. The success of MHP initiatives is contingent upon identifying suitable sites and remains challenging related to influencing parameters in site selection for the regional/national scale. Therefore, this study aimed to determine the essential influencing variables for MHP site selection by evaluating multiple variables related to the existing MHPs. The method used for analysis was the GeoDetector and Recursive Feature Elimination-Random Forest (RFE-RF) approach in the Geographic Information System (GIS) framework. Combining GeoDetector and RFE-RF models proves to be a potent tool for essential influencing variables screening in MHP site selection. The eight essential variables were obtained, down from nineteen original variables, with a better performance statistically. This hybrid approach considers spatial patterns in data for variable selection, ensuring alignment with the chosen machine learning method. This study result is expected to assist decision-makers in the preliminary evaluation stage of MHP site exploration and promote Indonesia’s transition to a cleaner, more renewable energy future and participatory forest conservation.

Solar Tracking and Monitoring System

Abstract: We will eventually have to deal with the depletion of fossil fuels and other non-renewable energy sources as they are running out rapidly. Having a large number of renewable alternative energy sources is crucial. The sun's radiation properties meet both requirements. As a result, new technologies focused on solar energy harvesting are starting to appear. Concentrated or photovoltaic panels may yield the highest efficiency. Due to the planet's rotation, which causes humans to view the sun at different times of the day the efficiency may reduce. Devices that direct a solar panel or concentrating panel during the day are incorporated in the design, along with light-trackers to boost the system's effectiveness. A solar tracker can monitor the sun's radiation in single direction. The device monitors daily tilt of the sun for optimal performance. The work focuses on the fundamentals of solar panel parameters and their application, as well as the design and construction of an automatic solar tracker prototype utilizing Arduino code based on microcontroller. By simulating the sun's 12-month tracking in a matter of minutes, the device incorporates automation mechanisms into the tracking system.